Acacia angustissima
(prairie acacia)

Preferred Common Name

• prairie acacia

Other Scientific Names

• Acacia angulosa Bertol.
• Acacia boliviana Rusby
• Acacia elegans M.Martens & Galeotti
• Acacia filicena Willd.
• Acacia filicioides (Cav.) Branner & Coville
• Acacia filicoides (Cav.) Trel.
• Acacia glabrata Schltdl.
• Acacia hirta Nutt.
• Acacia hirta Nutt. ex Torr. & Gray
• Acacia insignis M. Martens & Galeotti
• Acacia lemmonii Rose
• Acacia pittieriana Standl.
• Acacia suffrutescens Rose
• Acacia texensis Torr. & Gray
• Acaciella angulosa (Bertol.) Britton & Rose
• Acaciella angustissima (Mill.) Britton & Rose
• Acaciella costariciensis Britton & Rose
• Acaciella holtonii Britton & Killip
• Acaciella martensis Britton & Killip
• Acaciella rensonii Britton & Rose
• Acaciella santanderensis Britton & Killip
• Acaciella talpana Britton & Rose
• Mimosa angustissima Mill.
• Mimosa filicoides Cav.
• Mimosa ptericina Poir.
• Senegalia filicina (Willd.) Pittier

International Common Names

• English: fern acacia; prairie wattle; white-ball acacia
• Spanish: cantebo; cantemo; carboncillo; chilipac; guachillo; guaje; guajillo blanco; guajito; guapinico; huajillo; palo de pulque; timbe; timbre

Local Common Names

• Costa Rica: carboncillo
• El Salvador: guaje de bajillo
• Mexico: guajillo; timbe; timbre; xaax
• USA: barbas de chivo; cantemó; palo de pulque; prairie guajillo; Texas acacia

EPPO code

• ACAAG (Acacia angustissima)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Mimosoideae
•                                 Genus: Acacia
•                                     Species: Acacia angustissima

The genus Acacia was described by Philip Miller in 1754 and has a complex nomenclature and classification history (Maslin et al., 2003b). Acacia sensu lato, is polyphyletic, which prompted proposals and discussions on the reclassification of the genus (Maslin et al., 2003a; Kyalangalilwa et al., 2013).

Orchard and Maslin (2005) proposed the retypification of the genus from Acacia scorpioides (L.) W.F. Wright (=A. nilotica (L.) Willd. ex Del), distributed from Africa to India, to A. penninervis Sieb. ex DB, an Australian species. This proposal was adopted in the 2005 International Botanical Congress Nomenclature Session, and ratified in the 2011 International Botanical Congress, not without plenty of debate (McNeill and Turland, 2011; Smith and Figueiredo, 2011; Thiele et al., 2011). Rico Arce and Bachman (2006) reinstated the genus Acaciella for species that are native from the Southern USA to Argentina. The genus is characterized by the unarmed plants, lack of extrafloral nectaries and pollen in 8-celled polyads. Fifteen accepted species and five varieties are recognized by these authors. According to the changes proposed by the authors, Acaciella angustissima (Mill.) Britton & Rose should be the name used for Acacia angustissima (Mill.) Kuntze. It is a species with high morphological variability and extensive synonymy (Rico Arce and Bachman, 2006).

Acceptance of the new nomenclature has been slow or inconsistent. For example, Missouri Botanical Garden (2015), The Plant List (2013), and ILDIS (2015) still have not fully adopted all the changes. This datasheet follows the names being used at The Plant List (2013).

The following description is from the Flora of Panama (2015): Shrub or tree, the branchlets pubescent or puberulent to subglabrous, not noticeably lenticellate, longitudinally striate or angled. Leaves moderately large, bipinnate, the pinnae few to several pairs (about 15 pairs in Panamanian material cited), opposite or subopposite on the rachis, the leaflets numerous (up to 60 or more pairs per pinna); petiole up to a few cm. long, puberulent, eglandular, sulcate above; rachis up to 12 or more cm. long, like the petiole; pinnular rachis 3-9 cm long, somewhat margined, seemingly eglandular, bearing basally a pair of stipule-like leaflets; leaflets nearly linear, usually about 6 mm long and 1 mm. wide, acute (mostly bluntly so) apically, obliquely truncate basally, glabrous except ciliate-margined, dull above and below but darker above, the costa visible but secondary venation obscure; stipules linear-subulate, mostly 4-6 mm long. Inflorescence a terminal or subterminal panicle of pedunculate umbels (heads), these solitary to few-fasciculate from the (usually) defoliate nodes; peduncles usually about 1 cm long; floral bracts obovate-spatulate, little more than 1 mm long; pedicels mostly 1-2 mm long, borne from the terminus of the peduncle in umbellate or very short-spicate fashion. Flowers few to several per umbel, whitish; calyx campanulate or turbinate, about 1 mm long, glabrous or sometimes sparingly ciliate, the teeth short and broad; corolla funnelform, about 2 mm long, glabrous, the lobes divided almost to the base; stamens many, about 4 mm long, free except at the extreme base; anthers eglandular; ovary scarcely stipitate, glabrous or minutely puberulent, the style slightly exceeding the stamens. Legume linear- oblong, 4-8 cm long and about 1 cm wide, flat and thin, stipitate, glabrous in age; the seeds few, transverse.

A. angustissima has been the subject of research over the past 20-30 years, for its potential as a fodder and use in agroforestry (Dzowela, 1994; Cook et al., 2005). Most of these studies began in Australia, Indonesia, Papua New Guinea and Hawaii (Brook et al., 1994; Cole et al., 1996; Bray et al., 1997). In Australia, Pedley (1981) reported the species as present in 1965; it was planted in 1975 in Queensland for assessment for forage and fodder (Csurhes and Naive, 2009). Research with the species was abandoned in Australia since it has been considered a potential invasive weed (Gardiner et al., 2008). It is reported to be naturalized in the areas where it was planted and to have spread to neighbouring locations (Csurhes and Naive, 2009).

Research in Africa also started in the early 1990's and has been facilitated by the International Centre for Research in Agroforestry (ICRAF) to promote the species use for agroforestry and as a fodder (Dzowela, 1994; Dzowela et al., 1997). One of the countries where most of the planting has been done is Zimbabwe, where it has been made available to farmers and its reported as being highly desirable for agroforesty (Cook et al., 2005). It was introduced in the early 2000’s in Brazil (Paula et al., 2015) for its use as an intercropping tree in crop fields. It was introduced to Burkina Faso in 2005 with seeds coming from "Agroforester Tropical Seeds" from Hawaii (Bayala et al., 2009) for its use as a fodder and in site restoration. Martínez Quesada and Morales Pérez (2013) report it from Camaguey, Cuba; citing that the occurrence of few plants suggests an unintentional introduction, possibly resulting from dispersion by hurricane “Ike” in 2008.

Soil drainage

• free

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• light
• medium

Special soil tolerances

• infertile

A. angustissima has been introduced to various countries outside its native range because of its potential as a multi-purpose tree (Pedley 1981; Brook et al., 1992; Dzowela, 1994; Cole et al., 1996, Bray et al., 1997; Paula et al., 2015). Pedley (1981) cites different localities and collections for Queensland, Australia, where it was introduced as a forage plant. Bray et al. (1997) and Cole et al. (1996) give details on the introductions to Indonesia and Australia to study shrubby legume species for their potential as fodder. The International Centre for Research in Agroforestry (ICRAF) has various projects in the southern region of Africa, providing seeds and plants that could be used in agroforestry to improve crop production and feed livestock in order to ensure food security in the region (Dzowela, 1994; Bohringer, 2001). The species was also introduced in Brazil to improve crop production (Paula et al., 2015).

The recent introduction of the species to Cuba has led to the suggestion that it may have been introduced from the  southern USA to Cuba by Hurricane "Ike" in 2008 (Martínez Quesada and Morales Pérez, 2013).

A. angustissima leaves contain large amounts of nitrogen and a high percentage tannin content that can affect the digestion and absorption of nutrients and lower its palatability (Dzowela 1994; Bray et al., 1997). Odenyo et al. (2003) reported that the tannins and non-protein amino acids in its leaves had caused death in sheep, for which they suggested a gradual increase in the feeding of the Acacia leaves to cause adaptability and prevent toxicity. McSweeney et al. (2008) recommend further studies in ruminants to assess the links between these compounds and toxicity.

The use of A. angustissima for intercropping has not been recommended, because its rapid growth limits available light to other species, which inhibits their growth and/or affects crop yield (Brook, 1993;  Paula et al., 2015).

Although there is little information on the impacts of A. angustissima on habitats and/or biodiversity, Rico Arce and Bachman (2006) and Csurhes and Naive (2009) note that the species tends to be weedy or invasive in low deciduous forests and form thickets along roadsides and neighbouring areas, which can impact the habitats and the native species within. Its prolific seed production is a determining factor for the species becoming weedy (Bray et al., 1997). The seeds of A. angustissima have the ability to form long-lived seed banks; which for Australia were reported as still significant after five years without seed input (Gardiner et al., 2008).

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Tolerant of shade
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Monoculture formation
• Negatively impacts agriculture
• Negatively impacts forestry
• Negatively impacts animal health

• Competition - shading
• Poisoning
• Rapid growth

• Highly likely to be transported internationally deliberately

Economic value

A. angustissima has been extensively promoted as a multi-purpose tree outside its native range, as a fodder, to restore soil fertility, and to improve crop production in countries where there is no food security, soils have been degraded and there is the need for low cost options for agroforestry (Dzowela, 1994; Bohringer, 2001; Rincón-Rosales and Gutiérrez-Miceli, 2008). The species has been used as a protein supplement in areas where forage is limited due to difficult environmental and climatic conditions (McSweeney et al., 2008). As an intercrop hedgerow species, it has shown good results in Cameroon, where the tree prunings incorporated to the soil significantly increased maize yield (Akume et al., 2015).

Social benefit

The plant is an important medicinal species for the Tzotzil and Tzeltal Maya Indians in Mexico. It is used to cure diarrhoea, toothaches, rheumatism and skin lesions. It is also reported to inhibit growth in malignant tumours (Berlin and Berlin,1996). A. angustissima inhibits the growth of Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, and Candida albicans showing a potential to treat diseases (Hoffman et al.,1993).

The bark is used in Mexico in the fermentation of the beverages “tepache” and “pulque” (Rico Arce and Bachman, 2006). The common name "carboncillo" reported for Costa Rica, may refer to use as charcoal (Zamora, 1991).

Environmental services

Cook et al., (2005) report the following environmental services: reducing soil erosion, re-vegetation of disturbed areas, improvement of water quality, improving soils, and providing food and cover for small animals and wild birds.